With the development of communication technology, new requirements are proposed for the wireless network technology, i.e., a new generation of Wireless Fidelity (abbreviated as Wi-Fi) network of high rate, large scale and high throughput is required. The existing standard series of the Institute of Electrical and Electronics Engineers (abbreviated as IEEE) provide three channel access functions, including a Distributed Coordination Function (abbreviated as DCF), a Point Coordination Function (abbreviated as PCF) and a Hybrid Coordination Function (abbreviated as HCF). The DCF of Carrier Sense Multiple Access with Collision Avoidance (abbreviated as CSMA/CA), which is simple and convenient to be implemented, is a basic access mechanism and is used widely. As an optional access mechanism, PCF is based on DCF and performs centralized management on data transmission via a Point Coordinator (abbreviated as PC). HCF is a combination of DCF and PCF, and is used by a node which has Quality of Service (abbreviated as QoS) requirement. Therefore, the existing 802.11 IEEE standard series are based on contention. However, in a large scale network environment, the number of nodes which contend the channels at the same time is increased rapidly, thereby resulting in severe contention failure and thus lowering the network efficiency. In addition, the problem of hidden terminals in the wireless network may be more severe in the large scale network. It is indicated by a research that, in a network with infrastructure, the probability that any two nodes within the coverage area of a central node are hidden terminals is 41%. The problem of hidden terminals may become more severe with the increase of the network scale. If a delivery rate is 99% in a network without hidden terminal, the delivery rate is reduced to 94% in a network with hidden terminals of 5%. Therefore, the problem of hidden terminals is to be solved or alleviated urgently in a large scale network.
In view of this, the conventional technology can not satisfy people's new requirement on the wireless network, especially for the large scale network. Therefore, an appropriate solution is required to solve the problems brought by the large scale network.